Missing filter custom handling

[jkirschnik12]

Hello,

I was wondering if you'd ever consider adding support for overriding the behavior when a non-existent filter is used in the template string.

Currently if the filter is not found an exception is thrown (relevant code). Our company would like the ability to override this behavior.

Current:
(render "{{a | nonExistentFilter}}" {:a 1}) => Throws Exception: No filter defined with the name nonExistentFilter

Desired (for my use case):
(render "{{a | nonExistentFilter}}" {:a 1}) => "{{a | nonExistentFilter}}" no thrown exceptions.

I was thinking this would be similar to the work done in #130 where we'd allow users to override a var that would default to the existing behavior.

I'd be open to submitting a PR for this and have a proof of concept of the functionality.

Thanks!

[yogthos]

That sounds like a good idea, and a PR would be very welcome!